Team 314 Launcher

[RonnieS]

Originally Posted by Colin Small

I'm not quite sure what what you mean. Is it that you have it timed so that the gear isn't engaged (because of the three shaved teeth) when you want to poll the dog out? I'm confused....

Correct, the three "teeth" will be shaved down to make one circle in the gear that is all the same face measure. We also flipped the gearing so that the cylinder is pushing it into our driving gear instead of pulling it into the driving gear because cylinders work better pushing than pulling. Hope that is what you meant?

[RonnieS]

Originally Posted by IKE

Very impressive catapult. I look forward to seeing what you guys have together in robot form in just a few weeks.

Hopefully weeks changes to week...everyone is optimistic! aha. But thank you, it is coming together nicely so far, hopefully another competitive robot and a lot of fun in michigan!

[mrtravis2772]

Originally Posted by Ronnie314

We have a gen 1 shifter that I took the high gear out of and milled the teeth (3 of them)down to a flat face so that when the high gear transfers from low (winching the catapult back) to high (releasing into a free spin) where the dog has nothing to grab and the shaft releases to the direction of tension making the ball fly. On the output shaft there is an external ratcheting mechanism so that the tensions is released from the motors as it is drawn back. Also, we adjust our hard stop so we can get different angle shots such as a blop shot for a good truss toss.

can you give more details on the shifters?
is it a ball shifter(i was told that they wouldn't work)

[RonnieS]

Originally Posted by mrtravis2772

can you give more details on the shifters?
is it a ball shifter(i was told that they wouldn't work)

It is a Gen 1 AM shifter, modified for our needs. It uses a dog gear, not balls.

[mrtravis2772]

Originally Posted by Ronnie314

It is a Gen 1 AM shifter, modified for our needs. It uses a dog gear, not balls.

any chance you could demonstrate how that's done?
love the idea, think its genius!

[RonnieS]

Originally Posted by mrtravis2772

any chance you could demonstrate how that's done?
love the idea, think its genius!

Send me a private message and I will get with you on it!

[WaterClaw]

Originally Posted by Ronnie314

I do not know if this is sarcastic or not but 98% accuracy from anywhere inside the truss to goal area is pretty good in my book for a PROTOTYPE...The one miss was from not pulling back to the same spot attempting to see if less tension on the same dead stop point would give us more of a line drive rather then a tad bit of loft. And clearly shown, the less tension was not enough to make a half court shot...it was very valuable data for our team and proto testing. Again, this is not attacking just clarifying just in case it was not sarcastic. Thanks.

When firing forward, it worries me that the ball curves in flight when firing forward. I am simply stating facts. I like it, however it is inaccurate. Precision is clearly on par, but accuracy has me worried.

Granted it is a prototype, but I'm stating facts. The catapult system is ultimately unreliable if you cannot assert control over the x axis. With fine tuning yes, this will be rectified, but as to your prototype, it is inaccurate.

Regardless of the facts, I do not find it appropriate for you to ridicule what is clearly my personal opinion.

[Bob Steele]

Originally Posted by WaterClaw

When firing forward, it worries me that the ball curves in flight when firing forward. I am simply stating facts. I like it, however it is inaccurate. Precision is clearly on par, but accuracy has me worried.

Granted it is a prototype, but I'm stating facts. The catapult system is ultimately unreliable if you cannot assert control over the x axis. With fine tuning yes, this will be rectified, but as to your prototype, it is inaccurate.

Regardless of the facts, I do not find it appropriate for you to ridicule what is clearly my personal opinion.

I am curious as to your definitions of accuracy and precision.
I would also ask which axis you are determining to be the x axis?

I found this prototype to be quite accurate. In the initial shots it was not scoring... but as it moved in it was hitting nearly every time into the goal. After moving in the first time it showed that they had found something that was remarkable. The "sweet spot" was quite big. In this, I mean that the shooter could be several different distances from the goal, and still score.

The purpose of the shooter is to score a goal. If it does that it is accomplishing the task. One can define this as accuracy. The goals have a quite large margin for error side to side. (Is this the x axis as you defined?)

I found the shots to be quite precise by the standard definition ... given that they were moving up the apparatus by hand and often did not have it lined up quite the same. The ball was almost always in the same place in the goal and within 4-6 feet side to side.

Please understand that no one is ridiculing your statement. I honestly took it for sarcasm also when I first read your statement that the prototype was inaccurate. I thought that their prototype was amazingly accurate and the discovery of the large "sweet spot" was an eye opener for me.

Now my definition of accurate was being able to put the ball in the goal.
Evidently you must have a different definition. That is fine.

I showed this video to all of my designers... I thought it was remarkable to see the evidence that a shot could be taken from a number of different distances with the same stroke and power and still be successful.

This changes the way I see the game being played. It also may explain why there are no safe/protected zones. With goals as wide as these and the evidence in this video about what CAN be done with a simple launcher it changes the way I think offense will be done in the scoring zone.

Thank you for your comments

[RonnieS]

We viewed it as a "good launcher" based on it making it in the goal from a relatively good spread, "sweet spot". The misses were part of our data, we needed to know that we could not make it from under the truss, the location of our first miss. I was in no way attacking, you have your opinion. I would like to see your teams launcher though, it has to be amazing. I am dead serious about that too, maybe link to it after season starts???
Thanks, Ronnie.

[WaterClaw]

Originally Posted by Bob Steele

I am curious as to your definitions of accuracy and precision.
I would also ask which axis you are determining to be the x axis?

I found this prototype to be quite accurate. In the initial shots it was not scoring... but as it moved in it was hitting nearly every time into the goal. After moving in the first time it showed that they had found something that was remarkable. The "sweet spot" was quite big. In this, I mean that the shooter could be several different distances from the goal, and still score.

The purpose of the shooter is to score a goal. If it does that it is accomplishing the task. One can define this as accuracy. The goals have a quite large margin for error side to side. (Is this the x axis as you defined?)

I found the shots to be quite precise by the standard definition ... given that they were moving up the apparatus by hand and often did not have it lined up quite the same. The ball was almost always in the same place in the goal and within 4-6 feet side to side.

Please understand that no one is ridiculing your statement. I honestly took it for sarcasm also when I first read your statement that the prototype was inaccurate. I thought that their prototype was amazingly accurate and the discovery of the large "sweet spot" was an eye opener for me.

Now my definition of accurate was being able to put the ball in the goal.
Evidently you must have a different definition. That is fine.

Thank you for your comments

Precision is repeat-ability. To consistently make the same result with minimal outlying results. True, it can consistently score so repeat-ability is down pat. But accuracy is honed to a singled point as standard and all shots fired are referenced to said point.

If you intend to honestly say that "the entire goal is the single point of fire" then I am truly concerned as to your professionalism as a team. If you want to settle for just the goal as a posed to where in the goal, that's your decision. Simply put however, you must recognize that other robots will we doing considerably more.

The x-axis is left right by the way. Basic Geometry so I'm sure you know this. Just clarifying that I know what I'm saying.

Based on the direction being fired the ball had a most apparent tendency to curve in the air. True, averaging out all of your shots fired would result in a single point, which may be dead in front of your robot. However the target direction and the acquired result differed far too greatly at a distance. Even up close the x axis varies. You can never know how the game will play out and what will matter in the heat of the moment, and a short falling like that can and would be exploited.

[WaterClaw]

Originally Posted by Ronnie314

We viewed it as a "good launcher" based on it making it in the goal from a relatively good spread, "sweet spot". The misses were part of our data, we needed to know that we could not make it from under the truss, the location of our first miss. I was in no way attacking, you have your opinion. I would like to see your teams launcher though, it has to be amazing. I am dead serious about that too, maybe link to it after season starts???
Thanks, Ronnie.

You'll have to wait. We never release anything until the robot reveal at the end of build season. Standard policy.

[RonnieS]

Originally Posted by WaterClaw

You'll have to wait. We never release anything until the robot reveal at the end of build season. Standard policy.

I shall wait, hoping for a amazing robot!

[md2377]

How did you guys figure out the curvature of your catapult arm?

[Design006]

Originally Posted by Ronnie314

This is our final design review launcher, there is still evaluations being done but this video does a good job of showing our half court-in sweet spot. Hope you enjoy!!
https://www.youtube.com/watch?v=lWRYRpHFIaE

Here is the link for Intake and Shooter video, roughly 19 feet away.
https://www.youtube.com/watch?v=I1coTKRfynA

The shooter looks great as a prototype and the range looks great. I am looking forward to seeing it on a chassis and shoot from the winch. Great range! The ball does not have too much spin either. Make sure you are thinking about a gripping mechanism around the arm's cradle - that wood has a higher coefficient of friction and is gripping the ball more than the aluminum will. Think through some sticky tape or wrapping. Part of your success is the ball's spin or lack-there-of. Great job so far!

[stryker0603]

The majority of our side to side inaccuracy was due to the inconsistencies of the prototype. The wooden frame being held down by two people on tile as well as the shooter being released by one hand before the other. The shots were consistent, the direction the shooter was not. The three or four inches the front of the robot turned side to side becomes three or four feet side to side when shooting from 20 feet out.